Biomarker proxy IP25 shows potential for studying entire Quaternary Arctic sea-ice history

• Published in: Organic Geochemistry
• Main Authors: Stein, R., Fahl, K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2013
• Subjects: Arctic; Yermak Plateau; Fram Strait; Phytoplankton; Sea ice; Yermak plateau
• Online Access: https://oceanrep.geomar.de/id/eprint/25437/; https://oceanrep.geomar.de/id/eprint/25437/1/Stein%20et.al.pdf; https://doi.org/10.1016/j.orggeochem.2012.11.005

A novel and promising biomarker proxy for reconstruction of Arctic sea ice conditions was developed and is based on the determination of a highly branched isoprenoid with 25 carbons (IP25). IP25 records have been restricted to the last 150 kyr BP. We present a biomarker record from Ocean Drilling Program (ODP) Site 912, going back to the Pliocene–Pleistocene boundary and indicating that sea ice of variable extent occurred in the Fram Strait/southern Yermak Plateau area at least since about 2.2 Ma. Furthermore, our data support the idea that a combination of IP25 and open water, phytoplankton biomarker data (“PIP25 index”) may give a more reliable and quantitative estimate of past sea ice cover (at least for the study area). The study reveals that the novel IP25/PIP25 biomarker approach has potential for semi-quantitative paleo-sea ice studies covering the entire Quaternary and could motivate further detailed high resolution research on ODP/IODP material using this proxy.